What is the test for obtaining a warrant to draw a blood sample from a driver who is lawfully arrested for driving under the influence of alcohol?

The withdrawal of a blood sample constitutes a search governed by Fourth Amendment standards. (McNeely, supra, 133 S.Ct. at p. 1558.) A blood draw requires a physical intrusion into a person's skin and veins, and constitutes "an invasion of bodily integrity" that "implicates an individual's 'most personal and deep-rooted expectations of privacy.' " (Ibid.) Accordingly, even when a driver is lawfully arrested based on probable cause of intoxication, a warrant is required for a blood draw unless the government establishes by a preponderance of the evidence that an exception to the warrant requirement rendered the warrantless blood draw constitutionally permissible. (Ibid.; see People v. Rios (2011) 193 Cal.App.4th 584, 590.)